I don't think a 4BTA swap should be too difficult after looking at the other 4BTA swaps on the internet, I searched google. If you get the bread truck factory swap motor, the mounts drop down on a set of V8 mounts from what I have read. I think the regular boat style side mounts would be easier to fab into a truck frame with a straight axle.
One concern I have would be the 400 kickdown that you would have to do manually since the switch is one the pedal in most trucks.
Alternator, starter and shutdown solenoid + gauges. I would think a tach should be used until you were familiar with the engine. Tachs on diesels are wired to the alternator.
It appears the going rate on one of these with a turbo 400 or SM465 out of a bread truck is about $3000-3500 running. Half that needing a rebuild.